I successfully tested XLR connectors with a 2 phase grid system voltage of 28V and 14V and one neutral return. Hotplugging is okay for small loads, the neutral connects first before any of the phase contacts get in touch, so no risk of unwanted floating potentials. One problem I encountered is the cable diameter for the XLR connectors: 3x1.5mm² H07 is the maximum which fits into the cable relief of the XLR connectors. For longer cables and depending on the load, the losses are too high for just 3x1.5² - that's a major downside of the otherwise versatile 3pin XLR connectors.

we could grind the 2.5mm^2 copper wire to fit. Or solder such a thicker wire to a short piece of 1.5mm^2 - ... though I have seen your new draft on github, I am not happy with reinventing the wheel by adding another plug when there are already many proven ones.

My suggestion is to cross the common AC connectors, i.e. use the American et al. standard for our DC, and the European et alia standard AC plug for DC in America et al.